Consider what’s going on inside the hive this Spring. Do a mite assessment.
Three strategies I’ve found that always fail when battling varroa are:
1. Denial—“I haven’t seen any mites, so my mite levels must be low.”
2. Wishful thinking—“I haven’t seen very many mites, so I’m hoping and praying that my bees will be OK.”
3. Blind faith—“I used the latest snake oil mite cure, and it’s gotta work!” Randy Oliver 2006
A nice primer on types of assessments and interpreting their meaning is found here:
http://scientificbeekeeping.com/fighting-varroa-reconnaissance-mite-sampling/
&
http://scientificbeekeeping.com/sick-bees-part-11-mite-monitoring-methods/
“It is greatly surprising to me …….how few (beekeepers) make the effort to monitor the levels of parasites in their colonies! Even more surprising is that, despite the considerable expense, many blindly treat their colonies without any idea as to whether their bees are actually infected!” Randy Oliver